Solid poly(azidomethyl)benzene explosive composition

ABSTRACT

Poly(azidomethyl)benzenes having the formula 
     
         C.sub.6 H.sub.6-N (CH.sub.2 N.sub.3).sub.N 
    
     wherein n represents 3 to 6 inclusive. These compounds are for use as novelxplosives.

GOVERNMENTAL INTEREST

The invention described herein may be manufactured, used and licensed byor for the Government for Governmental purposes without payment to me ofany royalties thereon.

In general, this invention relates to poly(azidomethyl)benzenes for useas an explosive.

More particularly, this invention relates to poly(azidomethyl)benzeneshaving the formula:

    C.sub.6 H.sub.6-N (CH.sub.2 N.sub.3).sub.n

wherein n represents 3 to 6 inclusive which may be used as an explosive.

BACKGROUND OF INVENTION

Azidomethyl derivatives of benzene are known; they include 1,4-bis(azidomethyl) benzene (Jour. Amer. Chem. Soc. 79,3491 (1957)) andmonoazidomethylbenzene (Encyc. of Explosives and Related Items, Vol. 2,pg. B94). However, due to their physical properties, they have notproved of practical interest as explosives.

SUMMARY OF INVENTION AND DETAILED DESCRIPTION

The novel explosive compounds of this invention are prepared by heatinga poly(halomethyl)benzene with a metallic azide according to theequation:

    C.sub.6 H.sub.6-N (CH.sub.2 X).sub.N +MeN.sub.3 →C.sub.6 H.sub.6-N (CH.sub.2 N.sub.3).sub.N

wherein X is a halogen, usually chlorine or bromine, Me is a metal, andn represents 3 to 6 inclusive. The organic solvents which may be used asthe reaction medium include ethanol, acetone, ethylene glycol monoethylether, dimethyl sulfoxide, dimethyl formamide, and N-methylpyrrolidinone.

EXAMPLES OF PREPARATION

1. Preparation of hexakis (azidomethyl) benzene.

18.0 g. (0.028 mole) of hexakis (bromomethyl) benzene (prepared inaccordance with the Jour. Am. Chem. Soc. 100,2173 (1978) and 15.0 9.(0.23 mole) of sodium azide were reacted in 75 ml of dimethylformamideby mixing at 75°-80° C. for 1 hour. The reaction mixture was cooled andpoured into cold water to precipitate the white solid product which wasfiltered, washed and dried. The yield was 11.5 g. which is 100 percentof theory. The product melted with decomposition at 163° C., and againat the same temperature after recrystallization from dioxane and water.

The identity of the product as hexakis (azidomethyl) benzene was provenby infra-red spectrum, NMR spectral analysis, and elemental analysis forC, H, and N.

Upon heating, a pinch of the material melted on a spatula, and shortlythereafter detonated sharply.

2. Preparation of hexakis (azidomethyl) benzene.

0.5 g. of hexakis (bromomethyl) benzene, 0.4 g. of sodium azide, and 15ml. of dimethylformamide were mixed by stirring at room temperature for2 hours. The reaction mixture was poured into water, the solid wasfiltered, and washed with water and methanol. The yield of product was0.3 g. which was 100 percent of theory.

The product was proven to be hexakis (azidomethyl) benzene by meltingpoint and infra-red spectrum.

3. Preparation of 1,3,5-tris (azidomethyl) benzene.

1.3 g. (0.0034 mole) of 1,3,5-tris (bromomethyl) benzene (preparedaccording to Chem. Ber. 106,717 (1973), and 0.8 g. (0.12 mole) of sodiumazide were mixed in 15 ml. of dimethylformamide for 5 hours at 75° C.The reaction mixture was poured into water, and an oil separated whichwas extracted with methylene chloride. The solvent was removed and 0.7g. of the product, a colorless oil was obtained, which was 86 percent oftheory.

The above product was identified as 1,3,5-tris (azidomethyl) benzene byinfra-red spectrum.

A drop of the product was placed in a test-tube, and heated over a lowBunsen flame at which time it detonated with a loud report.

4. Preparation of 1,2,4,5-tetrakis (azidomethyl) benzene.

0.9 g. (0.002 mole) of 1,2,4,5-tetrakis (bromomethyl) benzene (preparedin accordance with J. Het. Chem. 983, (1973), and 1.0 g. (0.015 mole) ofsodium azide were mixed with stirring in 25 ml. of dimethylformamide for1 hour at 80° C. The reaction mixture was poured into water, and thesolids were filtered and dried. The product yield was 0.6 g. which was100 percent of theory. The melting point of the solid product was 50° C.It was identified as 1,2,4,5-tetrakis (azidomethyl) benzene by infra-redspectrum. The latter compound detonated upon heating above its meltingpoint.

5. Preparation of 1,3,5-tris(azidomethyl) -2,4,6-trimethylbenzene.

1.0 g. of 1,3,5-tris (bromomethyl) -2,4,6-trimethylbenzene and 0.70. ofsodium azide were mixed in 25 ml. of dimethylformamide for 1 hour at 75°C. The reaction mixture was poured into water, and the solid product wasfiltered. The yield of product was 0.6 g. which was 85 percent oftheory. The product melted at 60° C. upon recrystallization frommethylcyclohexane. The product was identified by infra-red spectrum.Upon heating above its melting point, the product flashed.

RESULTS

In general, hexakis (azidomethyl) benzene has been found to be a whitesolid melting at 165° C., which can be prepared from inexpensive rawmaterial. It contains nearly 62 percent azide nitrogen. It is moresensitive to impact than lead azide or styphnate, but less sensitive tofriction or electric charge. It is stable to heat when tested by theVacuum Stability Test, and stable to aqueous hydrolysis. It is suitablefor use as a hot-wire initiator but is less sensitive than leadstyphnate. The compound has been subjected to the mandatory testsrequired for qualification as an explosive.

More particularly, the cited hexakis (azidomethyl) benzene melts in acapillary at 162°-5° C. with gas evolution and darkening. On rapidheating on a spatula, the compound melts and shortly thereafterdetonates. It is insoluble in water, and does not undergo any changeupon heating in water for one week at 60° C. It is poorly soluble inorganic solvents but maybe recrystallized from tetrahydrofuran ortoluene. It has been found to undergo surface darkening upon prolongedexposure to light.

Specifically, the cited hexakis (azidomethyl) benzene is comparativelystable thermally. Its Auto-ignition Temperature is 173° C. which is inthe area of Composition B (174° C.). The Five Second ExplosiveTemperature of 255° C. was determined bny the closed-cup procedure. Ithas practically the same response as nitroguanidine. The ExplosionTemperature Test was ran with 20 mg. of explosive. At this lower dosage,the cited compound showed more disruption of the blasting cap, and moresplashing of the Woods metal than 40 mg. of RDX.

Further, the cited hexakis compound has a substantially lowerelectrostatic and friction sensitivity than other primary explosives. Inthe Hot-Wire Initiation Test, the substantially high voltage required isregarded as a safety factor.

In summary, the cited hexakis compound is insoluble in water, stable tohydrolysis, and poorly soluble in organic solvents. It has a density of1.392 g/cc, explodes in concentrated sulfuric acid, and graduallydarkens in light. It passed the Vacuum Stability Test for 40 hours at100° C., the Five Second Explosion Temperature is 255° C. The activationenergy is 30.8 K cal/mole and the Auto-ignition Temperature is 173°.

In conclusion note should be also be taken that the isomers 1,2,3 and1,2,4 of tris (azidomethyl) benzene, and the isomers 1,2,3,4 and 1,2,3,5of tetrakis (azidomethyl) benzene may be similarly prepared from theknown bromomethyl or chloromethyl analogues.

The foregoing disclosure is merely illustrative of the principles ofthis invention and is not to be interpreted in a limiting sense. I wishit to be understood that I do not desire to be limited to the exactdetails of construction shown and described because obviousmodifications will occur to a person skilled in the art.

What is claimed is:
 1. A solid explosive selected from the groupconsisting of:a. Hexakis (azidomethyl) benzene, b. 1,3,5-Tris(azidomethyl) benzene, c. 1,2,4,5-Tetrakis (azidomethyl) benzene.
 2. Thesolid explosive of claim 1 being Hexakis (azidomethyl) benzene.
 3. Thesolid explosive of claim 1 being 1,3,5-Tris (azidomethyl) benzene. 4.The solid explosive of claim 1 being 1,2,4,5-Tetrakis (azidomethyl)benzene.